Americans love their science fiction but may not be ready to bring it home just yet. A new study suggests that a majority of Americans worry that the technological advances they see coming down the pike in the next 50 years could result in “a change for the worse.”

According to Pew Research Center poll released Thursday, about two-thirds of respondents expressed concerns over the possibility of parents being able to intentionally alter the DNA of their unborn children (66 percent), robots taking over the role of primary caregiver for seniors and invalids (65 percent), and personal and commercial drones flying through much of US airspace (63 percent).

Just over half of respondents reported that the widespread adoption of implants or devices embedded in clothing that constantly feed information to the wearer could have negative consequences.

In fact, 59 percent of respondents expressed optimism that scientific and technological advances could improve their way of life overall, and only 11 percent of respondents said they are not looking forward to owning futuristic inventions. The majority of Americans appear to be eagerly awaiting the advent of flying cars and bikes, a vehicle for time travel, and futuristic health care that could extend human longevity and wipe out disease.

Eight out of 10 Americans expect that doctors will be able grow custom organs in laboratories for transplant patients.

We are still a long way from real-life versions of "Star Trek" teleporters – though 3 out of 5 respondents said that they expect such a capability to materialize in the next 50 years – and we still haven’t figured out what to do with the three seashells in "Demolition Man." But a whole slew of technologies first envisioned by fiction writers have already become realities.

Sci-fi writer William Gibson’s “cyberspace,” a term he first used in a 1982 short story, has become a major part of our everyday lives. Flip phones modeled after those used by Captain Kirk in the original "Star Trek" were all the rage in the early 2000s.

To engineers, inventors, and software developers, science fiction is the stuff of inspiration for the future.

However, science fiction also holds many cautionary tales for ways in which technology can get out of control.

Much of zombie-lore revolves around the idea of intentional modification of DNA could result in the production of monsters. The 1997 film "Gattaca" portrayed a grim future where too much understanding of genetics leads to discrimination of people seen as defective.

In Dean Koontz’s 1973 sci-fi novel "Demon Seed," which was adapted into a 1977 movie, a woman becomes imprisoned in her home by an artificially intelligent computer that taps into computerized controls that have been installed around the house for convenience.

While true artificial intelligence has so far proved elusive, more smart appliances that connect to the Internet are being integrated into the home. Think Nest’s smart thermostats and fire extinguishers and Samsung’s Internet refrigerator.

So far, at least, smart appliances, like smartphones, have been well received. However, as technology strays from hardware into the biological realm such as brain implants designed to improve memory and meat that is grown in a lab, far fewer Americans are willing to become early adopters, Pew found.

Despite the high-speed trajectory of technological innovation, Americans do see some limits to future capabilities. For instance, only 19 percent of Americans envision humans gaining any control over the weather and only one-third see colonization of other planets as a real possibility in the next 50 years.